forgot password function for mailusers

Hi,
is there an addon for ispconfig 3 that lets email users reset their forgotten password for their email accounts?
To me it seems, this is only possible for customers and not the email-accounts of them: Ispconfig demands a username and an email address to reset the password and email users' useranames consist of their email address. I understand that ispconfig does not have a function to store a "backup" email address, so this is why I'm asking for an "addon"